Method of making a disposable diaper having an integral container

ABSTRACT

An improved self-containable disposable diaper wherein a portion of the disposal pouch is slit so as to form integral, oppositely extending wings, the wings preferably having means thereon for completing the attachment of the diaper to an infant. A method is provided for forming the improved diaper featuring folding, slitting and refolding portion thereof which is to define the pouch and wings.

Sept. 24, 1974 METHOD OF MAKING A DISPOSABLE DIAPER HAVING AN INTEGRALCONTAINER 1971 2 Sheets-Sheet 1 Original Filed Feb. 1

c HASCHAAR 3,837,955

Sept. 24, 1974 c. H. SCHAAR 3,837,955 METHOD OF MAKING A DISPOSABLEDIAPER HAVING AN INTEGRAL CONTAINER Original Filed Feb. 1, 1971 2Sheets-Sheet 2 United States Patent 3,837,955 METHOD OF MAKING ADISPOSABLE DIAPER HAVING AN INTEGRAL CONTAINER Charles H. Schaar, LakeZurich, Ill., assignor to tColgate-llalmolive Company Originalapplication Feb. 1, 1971, Ser. No. 111,188, now Patent No. 3,731,689.Divided and this application Oct. 12, 1972, Ser. No. 296,982

Int. Cl. B321) 31/02 U.S. Cl. 156-211 4 Claims ABSTRACT OF THEDISCLOSURE An improved self-containable disposable diaper wherein aportion of the disposal pouch is slit so as to form integral, oppositelyextending wings, the wings preferably having means thereon forcompleting the attachment of the diaper to an infant. A method isprovided for forming the improved diaper featuring folding, slitting andrefolding the portion thereof which is to define the pouch and wings.

This is a division of application Ser. No. 111,188 filed Feb. 1, 1971,now Pat. No. 3,731,689.

This invention relates to a disposable diaper having an integral pouchand integral means for application to a baby, and to a method therefor.

U.S. Pat. 3,369,545 describes a disposable diaper and method of usewhich permits a soiled diaper to be contained within an integral pouchfor sanitary disposal. While such a structure is highly advantageous,particularly in situations Where immediate disposal of the soiled diaperis not feasible, it would be desirable if the diaper could be providedwith integral means for fastening without the necessity for pinning itto itself through the pouch.

Various pinless diapers have been previously described in theliterature. Thus, U.S. Pats. 2,627,858 and 3,089,494 describe diapershaving extensions provided with adhesive for fastening Without the needfor safety pins. Although such structures are functional, they requirethe use of additional material in providing the pinless function.

In accordance with this invention, a disposable diaper of the typedisclosed in the aforesaid U.S. Pat. 3,369,545 is provided with integralattachment means without the use of additional material. It will beapparent that the addition of function and structure without the use ofadditional material is economically attractive.

More specifically, the aforesaid diaper is improved by providing slitsin the outermost Wall of the pouch so as to define a pair of wingspreferably having a combined width substantially equal to the width ofthe wall, and operable to form wings integrally extending from said Wallin one of the waist regions of the diaper, According to the method ofthis invention, the pouch portion of the diaper is preferably made byflattening a tubular sheet of fluid impervious material to provide thetwo pouch walls and slitting through two opposing wall portions thereofalong a line transverse to the longitudinal axis of the tube from alongitudinal edge of the flattened tube partially across the width ofsaid flattened tube, and cutting a second slit along a line extendinglongitudinally from one end of the flattened tube to said transverseslit.

The structure of this diaper and the method therefor, will be betterunderstood by reference to the following description of the inventionand the accompanying drawings in which:

FIG. 1 is a perspective view of a baby wearing a diaper constructed inaccordance with the invention;

FIG. 2 is a front elevational view of the absorbent side of the diaperconstructed in accordance with the invention;

FIG. 3 is a rear elevational view similar to FIG. 2 except that thewings are folded outwardly so as to extend away from the diaper;

FIG. 4 is a sectional view taken along the line IV-IV of FIG. 3;

FIG. 5 is a rear elevational view of the diaper of FIG. 2 with the wingsfolded inwardly;

FIG. 6 is a fragmentary perspective view illustrating steps in thedisposal of the diaper of the invention; and

FIG. 7 is a schematic perspective view illustrating several of theimproved steps in the method of making the diaper in accordance with theinvention.

Referring to FIG. 1, the invention relates to a disposable diaperespecially adapted for wear by a baby 10, the diaper being the typewhich is thrown away after having been soiled. Referring now to FIGS.2-5, the invention particularly concerns the disposable diaper of thetype having a fluid absorbent pad 12 and at least two layers 14 and 16of fluid impervious sheet material attached to the pad 12 in such amanner as to form a pouch 18 (FIG. 4). The pad 12 preferably includes afluid pervious cover sheet 20 as illustrated in FIG. 4. The layers 14and 16 are connected at their edges 22, 24 and 26, these edges alsocoinciding with three of the edges 27, 28 and 29 respectively, of thepad 12 to define three of the edges of the diaper.

Various modifications are possible in the .construction of the diaper ofthis invention, as illustrated in FIGS. 8 and 9 of the aforementionedU.S. Pat. 3,369,545. For example, the longitudinal edges of the coversheet may be folded around the corresponding edges of the fluidabsorbent pad, in which case the width of the back sheet need not begreater than the width of the fluid absorbent body. In thisconstruction, the longitudinal edges of the back sheet are joined to thefolded around longitudinal edges of the cover sheet.

Alternately the cover sheet may be larger than the absorbent pad. Inthis embodiment, the edges of the back sheet are secured to the foldedaround edges of the cover sheet. The diaper may also be constructed withboth cover and back sheets having larger dimensions than the filler, andsecured together in any of the aforementioned manners. In any of theseembodiments, the pouch is formed by joining the impervious sheet at itslongitudinal edges and one of its edges along the width thereof to thecorresponding adjacent edges of the back sheet, as previously described.

Fluid impervious sheets 14 and 16 are preferably films of thermoplasticmaterials, thereby allowing construction of the diaper by heat sealingtechniques. Examples of suitable thermoplastic films are polyethylenefilms, polypropylene films, ethylene-acrylate copolymer films, vinylchloride polymer and copolymer films, etc.

Fluid absorbent pad 12 may be one of more plies of cellulosic sheeting,e.g., paper or non-woven fabric or a mass of loosely associated fiberssuch as cotton fibers or comminuted wood pulp commonly known as flufi'.

Cover sheet 20 can be a wet strength tissue paper, polyurethane foam, orpreferably a non-woven fabric of material such as cotton, rayon,polypropylene, nylon, etc.

In accordance with one aspect of the invention, the outermost layer 16is slit near one end 31 of the diaper along a line forming an edge 30(FIG. 3) at an angle to edges 22 and 24 and along a longitudinal centerline, to form a pair of integral wings 32 and 34 extending from oppositeedges 22 and 24 of the layers 14 and 16 and of the diaper. The Wings 32and 34 are foldably attached to the bottom layer 14 so that the diapercan be stored (FIG. 5) with the Wings 32 and 34 overlapping bottom layer14. Because the wings are formed by slitting the layer 16, it will bereadily apparent that the edges 36 and 38 of the wings are contiguouswith the slit edge 30 of the layer 16 when the wings are so overlapped.Also, the outermost edges 40 and 42 of the Wings are contiguous witheach other in that overlapped configuration, the combined width of thewings being that of the width of the layers 14 and 16 and therefore ofthe diaper.

When the diaper is to be placed on the baby, the wings fold outwardlyalong the edges 22 and 24 to give the configuration shown in FIGS. 2 and3. Although the wings 32 and 34 are disclosed as having approximateequal length, such is not necessary. Equal length does provide, however,a more aesthetic appearance.

In order to provide a contour fit of the Wings around the babys legswhen the diaper is attached as shown in FIG. 1, it is necessary thatedges 36 and 38 extend from the layer edges 22 and 24 at an angle lessthan 90. Accordingly, the value of the angle a (FIG. 3) should be lessthan 90 and preferably about 77. It will be readily appreciated thatbecause of the angle a differing from 90, the slit edge 30 forming thetop outside edge of the pouch 18 is angled. Since, as disclosed, thewings 32 and 34 have approximate equal width, the location of the anglein the slit edge 30 is approximately centered in the layer 16. Thus, thewings 32 and 34 increase in their width as they extend outwardly fromthe edges 22 and 24 to their outermost edges 40 and 42, respectively.The increased width provides the additional advantage of increasing theattaching strength of the Wings. The wing structure thus providesstronger attachment than could be had if conventional tape tabs wereapplied simply to the absorbent pad 12 or the liquid impervious sheet14. If desired, wings 32 and 34 can be further reinforced by any meanssuitable for reinforcing impervious sheeting, such as an additionallayer of liquid impervious film, strand reinforcements, etc., or byfolding etch wing back upon itself to provide a double thickness.

The pinless function of this diaper is preferably accomplished byapplying a pressure sensitive adhesive to the Zones indicated by thenumeral 50, FIGS. 2, 5 and 6. Any conventional pressure sensitiveadhesive can be used, examples being natural rubber combined withmodified wood resins and adhesives of the type disclosed in US. Pat.3,299,010. Removable facing strips may be applied to the adhesive Zones50, so that the wings do not stick until the diaper is ready for use.Alternately, doubleface pressure sensitive adhesive tabs can be used.The adhesive may be applied to an area other than zone 50; for example,it may be placed in a thinner or thicker band or as discrete spots.

The above-described diaper can be manipulated for disposal in a mannersimilar to the diaper disclosed in the aforesaid Pat. 3,369,545. Thatis, referring to FIG. 6 herein, the slit edge 30 of the layer 16 definesthe opening into the pouch 18 which permits the turning inside out ofthe diaper. When the dia er is soiled, one hand is then slipped into thepouch 18 to the edge 26 of the layer 16 where that edge is grasped. Atthe same time the other hand pulls on the slit edge 30 of the layer 16,the two hands crossing over so as to turn the pouch inside out. Theresulting configuration places the inside layer 14- completely exposedon one side of the folded up diaper with the layer 16 on the other side,the absorbent pad 12 being thus completely enclosed.

While the impervious sheet forming the wings and pouch need not beco-extensive With back sheet 16, it must have edges contiguous with atleast one of the edges along the width of the diaper in order that theWings be in the waist region thereof. Furthermore, the pouch 14 must beof adequate dimensions so as to contain the entire soiled diaper surfaceupon reversal.

In accordance with another aspect of the invention, FIG. 7 illustrates apreferred method of manufacturing this diaper. In accordance with thismethod, the two layers 14 and 16 of the impervious sheet are extruded asa single tubular sheet 60. The sheet 60 is flattened so as to form foldlongitudinal edges 62 and 64. The next step is to slit the flattenedsheet through two opposing wall portions transversely from fold edge 64along the slit line 66 only partially across the sheet. Preferably slit66 extends onehalf the width of flattened sheet 60. The line 66 isinclined to the fold 64 at an angle preferably less than 90, the angleon for example being on the order of about 77. A second slit is then cutalong the line indicated by numeral 68 which coincides with the foldedge 64 and intersects the slit 66 as well as the leading edge 70 of thetubular sheet which is to form end 31 of the diaper. The next step is tounfold the tubular sheet and refold it with a reorientation, so that thefolded edges form edges 22 and 24 of the pouch, these folded edges beingin the preferred embodiment substantially equidistant from the slit 68.One method of accomplishing this is to slide the tubular sheet over arefolding mandrel which comprises two planar surfaces intersecting eachother at approximately 90; 71 is a schematic view of a segment of such arefolding mandrel, which is known in the art. Thus, the reformed edgeswhich also coincide with the fold edges 22 and 24 will be formed alongthe edges 72 of the mandrel. The next step is to bring the slit andrefolded sheet into position for attachment to the absorbent pad 12 sothat the attachment can be made with the edges of the sheet and padproperly aligned.

It will be apparent that each individual diaper can be made inaccordance with the previous steps on an intermittent basis. Preferably,however, the previous steps are accomplished in a continuous processwhich proceeds in a manner illustrated in FIG. 7. Specifically, thetubular sheet 60 is rolled off a roll 74 having a length considerably inexcess of the length of an individual diaper, the slitting stepsoccurring periodically so as to space the slits along the tubular sheet60 as it unwinds from the roll 74. After a portion of the tubular sheetis so slit, that portion passes over the mandrel so as to be refolded.From the mandrel, the sheet continues on to a station which is oppositea long roll 78 of the absorbent pad 12. The roll 78 unwinds at the samespeed as the tubular sheet is traveling, and the sheet and the pad arebrought into superposition and continuously adhered or otherwiseattached to each other by an attaching station (not shown) usingtechniques such as heat sealing. Thereafter, individual diapers areperiodically severed from the continuous length of adhered pad andsheet, the severing being spaced so as to intercept the slits which wereformed along the line 68 at the point where it terminates at the top end31 of the diaper. The final severing not only produces each individualdiaper but completes the cut necessary to release the wings so that theycan be unfolded from the layer 16 when the diaper is ready to be used.The bottom edge 26 of the layers 14 and 16 is sealed in a concurrent orsubsequent operation. It will be recognized that this continuous processof making the improved disposable diaper reduces the cost by speeding upthe process.

Although the invention has been described in connection with certainpreferred embodiments, it is not intended that the invention be limitedthereto. For example, the only requirement with respect to the slits inthe pouch is that they assume a general T configuration. Thus, thelongitudinal slit can be positioned at any point along the width of thediaper, thus providing wings of unequal width. Also, the wings can betrimmed after manufacture to smaller dimensions. Furthermore, the twolayers of fiuid impervious sheet can be formed separately rather than asan integral tubular sheet, the two layers then being heat sealed attheir edges. Also, if desired, the pouch can open at both ends, allowingdisposal to be accomplished by inverting the diaper inside out at eitherend of the pouch. While slit has been illustrated as a continuousseverance, the term is meant to include such equivalents as a perforatedtear line. Thus, it is intended that the invention cover all alternativearrangements, equivalents, and embodiments as may be included within thescope of the following claims.

What is claimed is:

1. A method of making a disposable diaper which comprises:

a. providing a fluid absorbent body having a length and width sufficientto fit around and cover the lower portion of the torso of a human bodyfrom the waist at the back of the body over the crotch to the waist ofthe front of the body;

providing a tube of fluid impervious sheet material; flattening saidtube to provide two opposing, planar wall portions, said wall portionshaving a common longitudinal side edge along the length of the tubing;

. slitting said flattened tube (i) along a line transverse separatingthe walls of said flattened, slit tube; flattening said tube along foldlines parallel to and equidistant from said longitudinal slit;

g. positioning said tube on one side of said fluid absorbent body, theside of said tube having said slits facing outwardly; and

h. securing said tube to said fluid absorbent body.

2. The method of Claim 1 wherein said transverse slit extends one-halfthe width of said flattened tube.

3. The method of Claim 1 further comprising sealing said tube along theedge opposite the edge having said longitudinal slit extendingtherefrom.

4. The method of Claim 3 further comprising joining a fluid perviouscover sheet to the side of said fluid absorbent body away from saidtube.

References Cited UNITED STATES PATENTS 3,229,875 1/1966 Stoller 128-2873,369,545 2/1968 Wanberg 128-287 3,726,745 4/1973 Gidge et a1. 1565 10CHARLES E. VAN HORN, Primary Examiner M. G. WITYSHYN, Assistant ExaminerUS. Cl. X.R. 156-457; 8319

